The study reported here is part of a continuing program of research into pilot decision-making based on an information processing model of human decision-making under task-related stress. This model posits, inter alia, that experts and novices in a knowledge domain adopt different cognitive strategies in solving decision problems, and that these strategies are differentially affected by stress. The present experiment examined the effect of task-related stress upon aviation-relevant cognitive skills in trainee instrument pilots using SPARTANS, an automated test battery. The battery was administered under stress and control conditions, providing data on the effects of the stress manipulation upon putative cognitive components of decision-making independent of the criterion task - simulated flight using the MIDIS microcomputer system. The results provide evidence of stress related decrements in working memory, flexibility of closure, and spatial processes, but not in the retrieval of declarative knowledge. These results are discussed in the light of the model's predictions and previous empirical results using MIDIS.